Which nerve in the lumbar plexus is present in only about 10% of the population? A : accessory obturator nerve B : obturator nerve C : genitofemoral nerve D : iliohypogastric nerve E : ilioinguinal nerve

A : accessory obturator nerve

Explanation:

The accessory obturator nerve - found in about ten per cent of the population - is placed medial to the psoas major and anterior to the obturator nerve. It has a small size and emerges from the ventral divisions of the third and fourth lumbar nerves.

The obturator nerve is located on the ventral divisions of the second, third and fourth lumbar nerves in the lumbar plexus; the genitofemoral nerve is placed in the abdomen; the iliohypogastric nerve arises in the lumbar plexus and involves the lateral gluteal area and transverse abdominal muscles; while the ilioinguinal nerve operates from the first lumbar nerve to the iliohypogastric nerve.